Drive device for a movable furniture part

ABSTRACT

A drive device for a movable furniture part, comprising an ejection force accumulator which can be tensioned, an ejection element mechanically loaded by the ejection force accumulator and used to carry out an ejection movement of the moveable furniture part from a closed position into an open position. The ejection movement can be initiated by a compression movement of the movable furniture part into a compression position which is behind the closed position. The drive device also comprises a tensioning device for tensioning the ejection force accumulator with energy which can be emitted by the ejection movement. During the compression movement, at least 50% of the energy emitted by the ejection force accumulator during the ejection movement can be introduced into the ejection force accumulator by the tensioning device.

The invention concerns a drive device for a movable furniture part, comprising an ejection force storage member which can be tensioned, an ejection element for carrying out an ejection movement of the movable furniture part from a closed position into an open position, wherein the ejection movement can be initiated by an over-pressing movement of the movable furniture part into an over-pressing position which is behind the closed position, wherein the ejection element is force-actuated by the ejection force storage member and a tensioning device for tensioning the ejection force storage member with energy which can be released during the ejection movement. Further, the invention concerns an item of furniture with a furniture carcass, a movable furniture part and such a drive device.

Since many years in the industry of furniture fittings there are several kinds of drive devices in order to enable an easy ejection of a movable furniture part (as for example a drawer or a furniture door) from a closed position. Thereby, a user does not have to pull the movable furniture part in order to open it, but the user can activate or initiate the ejection or opening by an ease triggering movement (e. g. by over-pressing the movable furniture part). Some examples for this are disclosed in the documents WO 2012/084594 A1, WO 2014/114514 A1, WO 2014/165876 A1 and WO 2013/134799 A1.

Mostly, one problem with mechanical drive devices is how and where the ejection force storage member is tensioned. In the simplest versions an ejection force storage member is tensioned in the last closing movement section before reaching the closed position (e. g. according to the ballpoint pen principle). Then, during the ejection, the active ejection is carried out along the same movement section in opening direction.

However, there are also other drive devices where the ejection force storage member is tensioned further outward during opening or closing (thus not in the last closing or opening section). An example for this is specified in the AT 008 629 U1. A similar device is also disclosed in the DE 198 23 305 A1.

Now, however, with many known drive devices it is that depending on the force of the ejection force storage member or depending on the weight of the movable furniture part, the tensioning movement is considered to be disturbing. This means, there is no continuous and uniform opening or closing movement as indeed the tensioning of the ejection force storage member has to be carried out at least on a part of the opening and/or closing path. In this section, thus, the movement of the movable furniture part is less smooth.

Hence, the object of the present invention is to provide an improved drive device compared to the prior art. In particular, the drive device should be constructed in such a way that a largely smooth and uniform movement of the movable furniture part between the open position and the closed position is provided.

This object is attained by a drive device with the features of claim 1. Therefore, according to the invention it is provided that at least 50% of the energy released by the ejection force storage member during the ejection movement can be introduced into the ejection force storage member by the tensioning device during the over-pressing movement. With other words this means that the major part of the loading energy for the ejection force storage member is introduced in the ejection force storage member only in the over-pressing movement. With known constructions it is indeed so that mostly much more than 90% of the loading energy is introduced somewhere in the region of the opening or closing movement. A small and negligible part of the loading energy was already sometimes introduced during the over-pressing movement, as also during the over-pressing movement in several construction variants of so-called touch latch mechanisms it had to be pressed against the ejection force storage member (see e. g. WO 2011/143682 A1). Thus, a substantially smoother movement sequence of the movable furniture part is guaranteed, as not the complete part of the loading energy for the ejection force storage member has to be introduced before reaching the closed position.

Preferably it is provided that during the over-pressing movement at least 80% of the energy released by the ejection force storage member during the ejection movement can be introduced into the ejection force storage member by the tensioning device. In particular it is of a great advantage if during the over-pressing movement almost 100% of the energy released by the ejection force storage member during the ejection movement can be introduced into the ejection force storage member by the tensioning device. This means that the tensioning of the ejection force storage member is carried out as late as with reaching the closed position, hence between the closed position and the over-pressing position. With other words, the tensioning of the ejection force storage member is only carried out in the section of the over-pressing movement of the furniture part movement path.

According to a further aspect the present invention concerns a generic drive device, wherein the movable furniture part can travel a furniture part tensioning distance during tensioning of the ejection force storage member by the tensioning device, in which tensioning distance the ejection force storage member is movable from a relaxed or partly tensioned position along a force storage tensioning distance into a tensioned position, and wherein a furniture part ejection distance can be traveled by the movable furniture part during the ejection of the movable furniture part by the ejection element, in which ejection distance the ejection force storage member is movable from said tensioned position along a force storage relaxing distance into the relaxed or partly tensioned position.

Another problem which often occurs with the state of the art is that the loading of the ejection force storage member has to be carried out along a relative long furniture part movement path during opening and/or closing. Thus, a user has to carry out this relatively long tensioning movement.

A further object of the present invention thus is to improve such drive devices or to provide an alternative tensioning possibility.

This is attained in that the furniture part ejection distance is larger than the furniture part tensioning distance. This means, only a relative small furniture part movement path (furniture part tensioning distance) is used in order to still have available a larger furniture part movement path (furniture part ejection distance) for the ejection movement after the over-pressing.

Particularly preferred it is provided that the furniture part tensioning distance for the most part corresponds to a furniture part movement distance during the over-pressing movement. Put in other words it can thus be provided that during the over-pressing movement almost 100% of the energy released by the ejection force storage member during the ejection movement can be introduced by the tensioning device. Especially when the furniture part tensioning distance corresponds substantially exactly to the over-pressing movement, this has the advantage that a user does not recognize at all the tensioning during the normal furniture part movement path as the tensioning indeed only takes place during the over-pressing movement.

In order to reach a possibly short furniture part tensioning distance, it is preferably provided that the furniture part ejection distance is at least double, preferably at least four times, as large as the furniture part tensioning distance. The loading of the ejection force storage member and the unloading of the ejection force storage member does not have to be carried out with a linear energy output or a linear energy input. Rather, also curve progressions or differently steep loading or unloading sequences can be provided depending on the type and form of the spring or force storage member. Preferably it is appropriately provided that the, preferably along the furniture part tensioning distance averaged, proportion of the force storage tensioning distance to the furniture part tensioning distance during the over-pressing movement is larger than the, preferably along the furniture part ejection distance averaged, proportion of the force storage relaxing distance to the furniture part ejection distance during the ejection movement.

For the implementation of the present invention there are different specific embodiments. In the following two variants are explained in detail:

According to a first embodiment the drive device comprises a transmission device arranged between a tensioning element of the tensioning device and the ejection element. Here it is preferably provided that the transmission or the transmission ratio between the tensioning element and the ejection force storage member during tensioning of the ejection force storage member is different, preferably larger, than between the ejection element and the ejection force storage member during the ejection of the movable furniture part. This means that on a shorter path (furniture part tensioning distance) by means of the transmission device the same energy is introduced which is then released on a longer path (furniture part ejection distance). In this case it is preferably provided that the tensioning element and the ejection element are formed separately.

According to a specific example of this first embodiment it is preferably provided that the tensioning device comprises a housing, an axial bolt connected to the housing,

a tensioning disk rotationally supported on the axial bolt, the tensioning disk comprising latching elements, the tensioning element being eccentrically connected to the tensioning disk, a transmission disk rotationally supported on the axial bolt, the transmission disk comprising latching stops for the latching elements, and the ejection force storage member which is mounted with a first spring base to the tensioning disk and with a second spring base to the housing.

For an easy tensioning it is preferably provided that the tensioning disk can be rotated by the tensioning element relative to the transmission disk during the over-pressing movement, whereby the ejection force storage member arrives from said relaxed or partly tensioned position in said tensioned position, wherein in said tensioned position the tensioning disk is latched by means of at least one of the latching elements on one latching stop of the transmission disk.

As in this first embodiment the tensioning element is formed separately from the ejection element, which is preferably movably supported on the housing, it is preferably provided that a lever is movably supported via one end on the ejection element and the lever is eccentrically and movably connected on the other end to a gear wheel, wherein the gear wheel meshes with teeth arranged on the transmission disk. Thus, the ejection element can be actuated by means of the transmission disk. These components together with the tensioning disk, the ejection force storage member and the transmission disk form the transmission device.

In contrast to the first embodiment, no transmission based on a gear wheel transmission is carried out in the second embodiment. Rather, in the case of the second embodiment it is so that the ejection force storage member comprises a first spring base and a second spring base, wherein during tensioning of the ejection force storage member both spring bases are movable relative to a housing of the drive device and wherein during ejecting the first spring base is fixed relative to the housing and the second spring base is movable relative to the housing. Thereby, a smaller furniture part movement path can be used during tensioning by the movement of both spring bases in order to introduce the same energy which is then used for the ejection movement in a larger (only in one direction acting) furniture part movement path.

Particularly preferred this is improved in that the tensioning device comprises a first and a second movable tensioning element, each preferably being rotationally supported on the housing, wherein the first spring base of the ejection force storage member is mounted to the first tensioning element and the second spring base of the ejection force storage member is mounted to the second tensioning element. In this embodiment in contrast to the first embodiment it is of an advantage when the second tensioning element forms the ejection element. Thus, less parts are necessary.

Further it is preferably provided that during the over-pressing movement the first tensioning element and the second tensioning element are movable relative to each other and relative to the housing, whereby the ejection force storage member arrives from said relaxed or partly tensioned position in said tensioned position. In order to guarantee the movement of only one spring base, it is preferably provided that during the ejection movement one of the tensioning element, preferably the first tensioning element, is held to the housing during at least a large part of the ejection movement by means of a holding device.

Protection is also sought for an item of furniture with a furniture carcass, a movable furniture part and a drive device according to the invention for the movable furniture part.

Further details and advantages of the present invention are described more fully hereinafter by means of the specific description with reference to the embodiments illustrated in the drawings, in which:

FIG. 1 shows a perspective view of an item of furniture with a drive device,

FIG. 2 shows the furniture part movement path in comparison with the energy of the ejection force storage member according to the state of the art,

FIG. 3 shows the furniture part movement path in comparison with the energy of the ejection force storage member in a drive device according to the invention,

FIG. 4 shows an exploded view of a first embodiment of the drive device,

FIG. 5a -12 show the movement sequence of a drive device according to the first embodiment,

FIG. 13 shows an exploded view of a drive device according to the second embodiment,

FIG. 14 shows the drive device according to the second embodiment in an assembled state and

FIG. 15-21 show the movement sequence of the second embodiment of the drive device.

FIG. 1 shows an item of furniture 20 which comprises a furniture carcass 21 and a movable furniture part 2 in form of a furniture door. This movable furniture part 2 is situated in the open position OS. The movable furniture part 2 is movably supported on the furniture carcass 21 by means of two hinges 22. These hinges 22 are designed in such a way that an active retraction of the movable furniture part 2 into the closed position SS is carried out in the last section of the closing movement S running in closing direction SR. The hinges 22 can also comprise a damping device for a damped retraction of the movable furniture part. Moreover, a drive device 1 in form of an ejection device is mounted to the furniture carcass 21 by means of a housing 8 or a mounting plate. In this first embodiment the drive device 1 comprises a tensioning element 6 and an ejection element 4 formed separately from the tensioning element 6.

FIG. 2 schematically shows the furniture item movement distance M in comparison to the (loading) energy E of the ejection force storage member 3 in a drive device according to the state of the art. The whole furniture part movement distance M is illustrated horizontally. The furniture part movement distance M is composed of the closing movement S running in closing direction SR and the opening movement O running in opening direction OR. In the closing movement S the movable furniture part 2 initially moves from the second open position OS2 in a free-running to the first open position OS1. During this movement sequence no tensioning of the ejection force storage member 3 is carried out, wherefore the ejection force storage member 3 stays in the relaxed position E₀ (The subscript number after the “E” always corresponds approximately the loading percentage of the ejection force storage member 3 with energy E). Starting from the first open position OS1 the tensioning of the ejection force storage member 3 begins. This is indicated in that the loading energy E of the ejection force storage member 3 increases from the first open position OS1, till the ejection force storage member 3 is finally fully loaded in the over-pressing position ÜS of the movable furniture part 2. This means, the ejection force storage member 3 is in the tensioned position E₁₀₀. The force storage tensioning distance K_(S) is situated between this relaxed position E₀ and the tensioned position E₁₀₀. In principle, it is also possible that this force storage tensioning distance K_(S) is situated further outward, as this is indicated by the dashed line illustrated on the left side. This can especially be provided in the case when a separate retraction device for retracting the movable furniture part 2 into a closed position SS is provided. As is further illustrated in FIG. 2, the force storage tensioning distance K_(S) of the ejection force storage member 3 is traveled in that a user is actively pressing onto the movable furniture part 2 in closing direction SR. This active furniture part movement distance M corresponds to the furniture part tensioning distance M_(S) which extends between the first open position OS1 and the over-pressing position ÜS. As is illustrated in FIG. 2, the ejection force storage member 3 is only loaded for approximately 80% when reaching the closed position SS. In the case of specific construction examples the ejection force storage member 3 is mostly already much more loaded in the closed position SS than in this schematic illustration. The over-pressing movement Ü of the furniture part movement distance M is located between the closed position SS and the over-pressing position ÜS. As soon as the over-pressing movement Ü is finished and the user is no longer pressing in closing direction SR onto the movable furniture part 2, the ejection movement A begins by the unloading of the ejection force storage member 3. This ejection movement A equates to the furniture part ejection distance M_(A), in which the ejection force storage member 3 moves between the tensioned position E₁₀₀ along the force storage relaxing distance K_(E) till the relaxed position E₀. Thereby, the first open position OS1 is reached again. Thereafter, the movable furniture part 2 can be moved in a free-running till the complete open position OS2.

It is disadvantageous with this known movement sequence according to the state of the art that a user does not experience a uniform movement of the movable furniture part 2 in a large part of the furniture part movement distance M (specifically during the closing movement S), as indeed in the region of the force storage tensioning distance K_(S) starting from the first open position OS1 a larger force has to be actively applied onto the movable furniture part 2 compared to the case with a movable furniture part 2 being in a free-running.

Therefore, the large advantage of the present invention is illustrated in FIG. 3, whereupon the force storage tensioning distance K_(S) begins as late as when the closing position SS of the movable furniture part 2 is reached; or whereupon the large part of the loading energy E is only introduced in the ejection force storage member 3 when the closing position SS of the movable furniture part 2 is reached. Accordingly, the furniture part tensioning distance M_(S) is much shorter in FIG. 3. Specifically, this furniture part tensioning distance M_(S) corresponds to the over-pressing distance Ü. Thus, the full energy E is introduced into the ejection force storage member 3 in a relative short section of the furniture part movement distance M during the over-pressing movement Ü by moving the ejection force storage member 3 from the relaxed position E₀ (corresponds to the closing position SS) along the force storage tensioning distance K_(S) into the tensioned position E₁₀₀ which corresponds to the over-pressing position ÜS of the movable furniture part 2. As soon as a user is no longer pressing onto the movable furniture part 2 in this over-pressing position ÜS, the ejection movement A is carried out similar to or same as in the already known drive devices. This means, this ejection movement A corresponds to the furniture part ejection distance M_(A) which is substantially larger than the furniture part tensioning distance M_(S). Once the first open position OS1 is reached, the movable furniture part 2 can again be moved in a free-running until the fully open position OS2.

In FIG. 3 the loading energy E of the ejection force storage member 3 is indicated with the continuous line. In this case this line is illustrated idealized. Of course, here can be deviations. Especially, the loading energy can also be increase progressively or non-linearly. There can also be differently steep sections during tensioning as well as during relaxing. This FIG. 3 shall schematically illustrate the averaged progress between the relaxed position E₀ and the tensioned position E₁₀₀.

Beside the basic explanation of the inventive idea, in FIG. 3 also still slightly modified variants are indicated by the dot-dashed lines.

The dot-dashed line on the right side corresponds to the first specific embodiment of the drive device 1. In this case it is so that at the end of the ejection movement A the ejection force storage member 3 is in said relaxed or partly tensioned position E₀₋₅₀ in which the ejection force storage member 3 is still partly tensioned and contains residual energy E_(R), wherein by this residual energy E_(R) of the ejection force storage member 3 the ejection element 4 is movable in closing direction SR along an ejection element returning distance A_(R) after travelling an ejection element ejection distance A_(A). Thus, only a part of the (loading) energy E introduced in the furniture part tensioning distance M_(S) is also used as (ejection) energy for the ejection. The residual energy ER is specifically used for the returning movement of the ejection element 4 into an initial position.

The dot-dashed line on the left side corresponds to the second specific embodiment of the drive device 1. In this case it is so that in the closed position SS of the movable furniture part 2 the ejection force storage member 3 is in said relaxed or partly tensioned position E₀₋₅₀, wherein when reaching the closed position SS the ejection force storage member 3 is already partly tensioned by a closing movement S of the movable furniture part 2. This means that the tensioning of the ejection force storage member 3 already begins before reaching the closed position SS. The large part, namely over 50%, of the loading energy E is still introduced in the ejection force storage member 3 only between the closed position SS and the over-pressing position ÜS.

For the comparison between the furniture part tensioning distance MS and the furniture part ejection distance M_(A), however, it is necessary in both embodiments to compare the same relaxed or partly tensioned position E₀₋₅₀ of the force storage tensioning distance K_(S) with the same relaxed or partly tensioned position E₀₋₅₀ of the force storage relaxing distance K_(E). It is possible from this to always derive that the furniture part tensioning distance M_(S) is smaller than the furniture part ejection distance M_(A).

In FIG. 3 it can additionally be discerned that the proportion K_(S):M_(S) of the force storage tensioning distance K_(S) to the furniture part tensioning distance M_(S) during the over-pressing movement Ü is about 9:1. In contrast, the proportion K_(E):M_(A) of the force storage relaxing distance K_(E) to the furniture part ejection distance M_(A) during the ejection movement A is about 9:6 or 3:2 respectively. Thereby, the proportion K_(S):M_(S) is larger than the proportion K_(E):M_(A). The inclination approximately corresponds to the transmission from the furniture part tensioning distance M_(S) to the force storage tensioning distance K_(S) and from the force storage relaxing distance K_(E) to the furniture part ejection distance M_(A) respectively.

FIG. 4 shows an exploded view of the first embodiment of a drive device. This drive device 1 comprises a housing 8 (base plate). The axial bolt 9 is mounted to this housing 8. The tensioning disk 10 is rotationally supported on the axial bolt 9 by means of the recess 23. Further, the transmission disk 12 is rotationally supported on the axial bolt 9 by means of the recess 24. The ejection force storage member 3 in form of a leg spring is coiled or arranged around the axial bolt 9. The ejection force storage member 3 is held by the first spring base F₁ in the recess 27 of the tensioning disk 10. The ejection force storage member 3 is held by the second spring base F₂ in the recess 26 of the housing 8. The tensioning disk 10 comprises in total six regularly arranged latching elements 11 in form of spring tongues. This spring tongues or latching elements 11 correspond with the six latching stops 13 formed in the transmission disk 12. An eccentrically arranged recess 25 is formed in the tensioning disk 10. A bolt of the tensioning element 6 engages in this eccentrically arranged recess 25. This tensioning element 6 is guided between the guiding elements 31. On the outer circumference of the transmission disk 18 a plurality of teeth 18 is arranged which mesh with the teeth of the gear wheel 17. This gear wheel 17 is rotationally supported in a rotary bearing 29 in the housing 8 by means of a rotary bolt 34. Further, an eccentric axis 30 is arranged on the gear wheel 17. An end 16 of the lever 14 is connected to this eccentric axis 30 by means of the lever pivot bolt 33. On the other end 15 of the lever 14 the lever 14 is connected to the ejection element 4 by means of the lever pivot bolt 33. This ejection element 4, in turn, is guided in the guiding 28 formed in the housing 8.

The drive device 1 is illustrated in the FIGS. 5a and 5b in different perspectives. The movable furniture part 2 is in the closed position SS. In this closed position SS the movable furniture part 2 abuts the tensioning element 6. As the ejection force storage member 3 slightly force-actuates the tensioning disk 10 counterclockwise, the latching elements 11 of the tensioning disk 16 abut the latching stops 13 of the transmission disk 12. The ejection force storage member 3 is in the substantially relaxed position E₀.

If now pressing onto the movable furniture part 2 in closing direction SR according to the FIGS. 6a and 6b , also the tensioning element 6 is moved in closing direction SR. Because this tensioning element 6 is rotationally supported on the eccentrically arranged recess 25 of the tensioning disk 10, also the tensioning disk 10 is rotated clockwise around the axial bolt 9. Consequently, the ejection force storage member 3 reaches the partly tensioned position E₅₀. By this movement of the tensioning element 6 in closing direction SR, the tensioning disk 10 is rotated clockwise relative to the transmission disk 12. Thereby, the latching elements 11 raise from the latching stops 13 and glide—with a slight bending of the latching elements 11 formed as spring tongues—along the underside of the transmission disk 12.

In FIGS. 7a and 7b the subsequent over-pressing position ÜS of the movable furniture part 2 is shown, in which the tensioning element 6 is fully pushed in. Thereby, the latching elements 11 are latched in the (clockwise) nearest recesses with the latching stops 13 in the transmission disk 12. According to FIGS. 7a and 7b the tensioning disk 10 has been rotated around 60° compared to the FIGS. 5a and 5b . This equals to the force storage tensioning distance K_(S) which corresponds with the (relatively short) furniture part tensioning distance M_(S) (see FIG. 5a ). In FIG. 7a the ejection force storage member 3 is in the tensioned position E₁₀₀.

Once the movable furniture part 2 is released in this over-pressing position ÜS, the ejection force storage member 3 can be relaxed till the partly relaxed position E₇₀ as indicated in the FIGS. 8a and 8b . As this relaxing movement of the tensioning disk 10 is carried out counterclockwise, also the transmission disk 12 is moved counterclockwise by means of the latching elements 11 and the latching stops 13. Based on the teeth 18 of this transmission disk 12 which mesh with the teeth of the gear wheel 17, the gear wheel 17 is rotated clockwise. As thereby also the eccentric axis 30 connected with the gear wheel 17 and, thus, also the lever 14 by means of the lever pivot bolt 32 moves, also the ejection element 4 is moved in opening direction OR. As this ejection element 4, in turn, abuts the movable furniture part 2, the ejection movement A of the movable furniture part 2 is initiated.

According to FIGS. 9a and 9b the gear wheel 17 has carried out a half revolution, whereby the ejection element ejection distance A_(A) is completed. This ejection element ejection distance A_(A) equals the furniture part ejection distance M_(A). Thereby, the movable furniture part 2 reaches the first open position OS1. As, however, in this first open position OS1 the ejection force storage member 3 has only relaxed about halfway and thus is in the partly relaxed position E₅₀, residual energy E_(R) remains in the ejection force storage member 3.

In FIG. 10 it is illustrated that e. g. based on the ejection momentum the movable furniture part 2 is distanced from the ejection element 4. This can also be carried out in that a user is actively pulling the movable furniture part 2.

In the FIGS. 11 and 11 b it is illustrated that the residual energy E_(R) of the ejection force storage member 3 has unloaded. Thereby, also the gear wheel 17 has been again moved to its starting position and the ejection element 4 is completely retracted. The tensioning element 6, as well as the ejection force storage member 3 and the tensioning disk 10, are again in the initial position according to the FIGS. 5a and 5 b.

In FIG. 12 also the movable furniture part 2 has again been moved to the closed position SS by means of the hinges 22. The movable furniture part 2 abuts the tensioning element 6. Beginning from this closed position SS a new tensioning movement of the ejection force storage member 3 can again be started.

In FIG. 13 an exploded view of the second embodiment of a drive device 1 is illustrated. In this case the housing 8 comprises the three housing parts 8 a, 8 b and 8 c. In this case the tensioning device 5 comprises the first tensioning element 6 a, the ejection force storage member 3 and the second tensioning element 6 b. The axial bolt 9 is attached to the holding recess 37 on the housing part 8 a. The first tensioning element 6 a as well as the second tensioning element 6 b is rotationally supported on the axial bolt 9. The first spring base F₁ of the ejection force storage member 3 is held in the recess 27 of the first tensioning element 6 a. The second spring base F₂ of the ejection force storage member 3 is held in the recess 26 of the second tensioning element 6 b. An elongated hole 35 is formed in the second tensioning element 6 b. A limit bolt 36 of the first tensioning element 6 a engages the elongated hole 35. Further, the drive device 1 comprises a holding device 19 for a tensioning element 6 a, 6 b. This holding device 19 comprises a rotary bearing 38 attached to the housing 8. The swiveling lever 39 is pivotally supported ton this rotary bearing 38. On this swiveling lever 39, in turn, a guiding roll 41 is movably attached. The tension spring 40 is held on the one hand on the swiveling lever 39 and on the other hand on the housing 8.

In FIG. 14 the drive device 1 according to the second embodiment is illustrated in an assembled state. It is also illustrated that in this case the second tensioning element 6 b forms the ejection element 4 of the drive device 1.

According to FIG. 15 a top view of the drive device 1 with the movable furniture part 2 is shown. In this case the movable furniture part 2 is in an open position OS. As no external pressure acts onto the tensioning elements 6 a and 6 b, the ejection force storage member 3 is in the relaxed position E₀. This relaxed position E₀ is limited in that the limit bolt 36 abuts the elongated hole 35 on the right side. Thus, there can be quite a certain residual energy in the ejection force storage member 3. This relaxed position E₀, thus, insofar corresponds to an “energy-free” ejection force storage member 3 as it is determined by the limit stop 36 and the elongated hole 35. The tension spring 40 of the holding device 19 is relaxed and presses the guiding roll 41 to the second tensioning element 6 b.

If now according to FIG. 16 the movable furniture part 2 is moved in closing direction SR, so both tensioning elements 6 a and 6 b initially move synchronously around the axial bolt 9 till according to FIG. 16 the first tensioning element 6 a abuts the limit stop 42 of the housing 8. In this FIG. 16 the ejection force storage member 3 is still in the relaxed position E₀.

If the movable furniture part 2 is then further pressed in closing direction SR, the drive device 1 reaches the position according to FIG. 17. In this FIG. 17 the ejection force storage member 3 is already tensioned to a part and is thus in a partly tensioned position E₅₀. The movable furniture part 2 is approximately in the closed position SS in which the movable furniture part 2 abuts the second tensioning element 6 b as well as the first tensioning element 6 a. Because the movable furniture part 2 (in an ideal case exactly starting from the closed position SS) abuts both tensioning elements 6 a and 6 b, both tensioning elements 6 a and 6 b are moved relative to the housing 8 and to each other. The second tensioning element 6 b moves clockwise, whereas the first tensioning element 6 a moves counterclockwise. By this relative movement of the tensioning elements 6 a and 6 b to each other, also the spring bases F₁ and F₂ are shifted to each other. The change of the tension of the ejection force storage member 3 can also be seen in the position of the limit bolt 36 in the elongated hole 35.

According to FIG. 18 the movable furniture part 2 has still further moved in closing direction SR, whereby the ejection force storage member 3 already is in a partly tensioned position E₇₀.

As soon as according to FIG. 19 the movable furniture part 2 fully abuts the housing 8 or the furniture carcass 21 respectively, the over-pressing position ÜS of the movable furniture part 2 is reached. Thereby, also the tensioned position E₁₀₀ of the ejection force storage member 3 is reached. Thus, both spring bases F₁ and F₂ each have traveled a part of the force storage tensioning distance K_(S). As the feed roller 41 does no longer abut one of the tensioning elements 6 a or 6 b, also the tension spring 40 can relax and rotates the swiveling lever 39 counterclockwise. The limit bolt 36 has reached the left-sided end of the elongated hole 35.

As soon as in the position according to FIG. 19 a user is no longer pressing onto the movable furniture part 2, the ejection force storage member 3 begins to relax as shown in FIG. 20 (in this case the energy E or the triggered turning moment of the ejection force storage member 3 has to be higher than the closing force of the hinges 22). As the feed roller 41 of the holding device 19 abuts the limit stop 43 of the first tensioning element 6 a, this tensioning element 6 a cannot rotate or relax clockwise. Hence, the whole loading energy E of the ejection force storage member 3 is only used for a relative movement of the spring base F₂ to the housing 8. Thereby, only the second tensioning element 6 b—which thus forms the ejection element 4—is moved in opening direction OR.

In FIG. 21 the ejection movement A is completed which corresponds to the furniture part ejection distance M_(A). As also illustrated in FIG. 21, the loading energy E of the ejection force storage member 3 was only used for moving the second tensioning element 6 b, whereby the force storage relaxing distance K_(E) has been traveled. Consequently, also in this embodiment the furniture part tensioning distance M_(S) is smaller than the furniture part ejection distance M_(A). In FIG. 21 also the swiveling lever 39 of the holding device 19 has again rotated clockwise, as the feed roller 41 abuts the deflection ramp 44 of the second tensioning element 6 b and is forced back by the deflection ramp 44 and, thus, the holding position of the first tensioning element 6 a is released. In FIG. 21 also the limit bolt 36 has again reached the right-sided end of the elongated hole 35, whereby the ejection force storage member 3 is in the relaxed position E₀.

Generally it has to be noted that the ejection force storage member can be for example an electromagnetic or pneumatic force storage member or an accumulator. Preferably the force storage member is formed as a spring. In this case the design of the spring, in turn, is again arbitrary. So the spring for example can be formed as a pressure spring, a tension spring or similar. In both embodiments the ejection force storage member is formed as a leg spring, wherein of course also other kinds of springs can certainly be used in the same functional manner. This is especially the case when no rotary movement for the loading of the ejection force storage member is used.

Further it is being noted that the drive device can certainly comprise also a locking device for locking the ejection element in a locking position. The locking device can preferably comprise a heart-curve shaped guide track. In the described embodiments the “locking” in the closed position is reached in that the hinges hold the movable furniture part closed. Moreover, a “locking” is also not necessary in contrast to many known drive devices in the state of the art, because the ejection force storage member is indeed not yet or hardly tensioned in the closed position.

It shall further be mentioned that all preferred features apply for both embodiments—as long as it is possible and functionally reasonable.

Concerning the aspect of the invention, whereupon during the over-pressing movement at least half of the ejection force storage member loading energy is introduced, it should be noted that this can be carried out independently of the proportion of the furniture part tensioning distance to the force storage tensioning distance. This advantage of the “tensioning during over-pressing” is thus also given when the furniture part ejection distance is as large—or as “short”—as the furniture part tensioning distance during the over-pressing. Conversely, the shorter furniture part tensioning distance compared to the furniture part ejection distance is not necessarily dependent thereon, whether this “short” furniture part tensioning distance is in the region of the over-pressing movement. Rather, this “short” furniture part tensioning distance can also be somewhere between the second open position and the closed position. Preferably both aspects of the invention are implemented in a drive device, as it is also the case with the two specific embodiments.

LIST OF REFERENCE SIGNS

-   1 drive device -   2 movable furniture part -   3 ejection force storage member -   4 ejection element -   5 tensioning device -   6 tensioning element -   6 a first tensioning element -   6 b second tensioning element -   7 transmission device -   8 housing -   8 a housing part -   8 b housing part -   8 c housing part -   9 axial bolt -   10 tensioning disk -   11 latching elements -   12 transmission disk -   13 latching stops -   14 lever -   15 end of the lever -   16 other end -   17 gear wheel -   18 teeth on the transmission disk -   19 holding device -   20 item of furniture -   21 furniture carcass -   22 hinge -   23 axial recess -   24 axial recess -   25 eccentrically arranged recess -   26 recess for the second spring base -   27 recess for the first spring base -   28 guiding -   29 rotary bearing -   30 eccentric axis for the gear wheel -   31 guiding elements -   32 lever pivot bolt -   33 lever pivot bolt -   34 rotary bolt -   35 elongated hole -   36 limit bolt -   37 holding recess for the limit bolt -   38 rotary bearing -   39 swiveling lever -   40 tension spring -   41 feed roller -   42 limit stop -   43 limit stop -   44 deflection ramp -   A ejection movement -   Ü over-pressing movement -   S closing movement -   O opening movement -   M furniture part movement distance -   SS closed position -   OS open position -   OS1 first open position -   OS2 second open position -   ÜS over-pressing position -   SR closing direction -   OR opening direction -   E (loading) energy -   M_(S) furniture part tensioning distance -   M_(A) furniture part ejection distance -   E₀₋₅₀ relaxed or partly tensioned position -   E₆₀ partly tensioned position -   E₇₀ partly tensioned position -   E₁₀₀ tensioned position -   K_(S) force storage tensioning distance -   K_(E) force storage relaxing distance -   F₁ first spring base -   F₂ second spring base -   E_(R) residual energy -   A_(A) ejection element ejection distance -   A_(R) ejection element returning distance 

1. A drive device for a movable furniture part, comprising an ejection force storage member which can be tensioned, an ejection element for carrying out an ejection movement of the movable furniture part from a closed position into an open position, wherein the ejection movement can be initiated by an over-pressing movement of the movable furniture part into an over-pressing position which is behind the closed position, wherein the ejection element is force-actuated by the ejection force storage member and a tensioning device for tensioning the ejection force storage member with energy which can be released during the ejection movement, wherein at least 50% of the energy released by the ejection force storage member during the ejection movement can be introduced into the ejection force storage member by the tensioning device during the over-pressing movement.
 2. The drive device according to claim 1, wherein at least 80% of the energy released by the ejection force storage member during the ejection movement can be introduced into the ejection force storage member by the tensioning device during the over-pressing movement.
 3. The drive device according to claim 1, wherein almost 100% of the energy released by the ejection force storage member during the ejection movement can be introduced into the ejection force storage member by the tensioning device during the over-pressing movement.
 4. The drive device according to the preamble of claim 1, wherein the movable furniture part can travel a furniture part tensioning distance during tensioning of the ejection force storage member by the tensioning device, in which tensioning distance the ejection force storage member is movable from a relaxed or partly tensioned position along a force storage tensioning distance into a tensioned position, and wherein a furniture part ejection distance can be traveled by the movable furniture part during the ejection of the movable furniture part by the ejection element, in which ejection distance the ejection force storage member is movable from said tensioned position along a force storage relaxing distance into the relaxed or partly tensioned position, wherein the furniture part ejection distance is larger than the furniture part tensioning distance.
 5. The drive device according to claim 4, wherein the furniture part tensioning distance for the most part corresponds to a furniture part movement distance during the over-pressing movement.
 6. The drive device according to claim 4, wherein the furniture part ejection distance is at least double, preferably at least four times, as large as the furniture part tensioning distance.
 7. The drive device according to claim 4, wherein the, preferably along the furniture part tensioning distance averaged, proportion of the force storage tensioning distance to the furniture part tensioning distance during the over-pressing movement is larger than the, preferably along the furniture part ejection distance averaged, proportion of the force storage relaxing distance to the furniture part ejection distance during the ejection movement.
 8. The drive device according to claim 4, wherein a transmission device arranged between a tensioning element of the tensioning device and the ejection element, wherein the transmission ratio between the tensioning element and the ejection force storage member during tensioning of the ejection force storage member is different, preferably larger, than between the ejection element and the ejection force storage member during the ejection of the movable furniture part.
 9. The drive device according to claim 8, wherein the tensioning element and the ejection element are formed separately.
 10. The drive device according to claim 8, wherein the tensioning device comprises a housing, an axial bolt connected to the housing, a tensioning disk rotationally supported on the axial bolt, the tensioning disk comprising latching elements, the tensioning element being eccentrically connected to the tensioning disk, a transmission disk rotationally supported on the axial bolt, the transmission disk comprising latching stops for the latching elements, and the ejection force storage member which is mounted with a first spring base to the tensioning disk and with a second spring base to the housing.
 11. The drive device according to claim 10, wherein the tensioning disk can be rotated by the tensioning element relative to the transmission disk during the over-pressing movement, whereby the ejection force storage member arrives from said relaxed or partly tensioned position in said tensioned position.
 12. The drive device according to claim 11, wherein in said tensioned position the tensioning disk is latched by means of at least one of the latching elements on one latching stop of the transmission disk.
 13. The drive device according to claim 10, wherein a lever is movably supported via one end on the ejection element and the lever is eccentrically and movably connected on the other end to a gear wheel, wherein the gear wheel meshes with teeth arranged on the transmission disk.
 14. The drive device according to claim 8, wherein at the end of the ejection movement the ejection force storage member is in said relaxed or partly tensioned position, in which the ejection force storage member is still partly tensioned and comprises residual energy, wherein by this residual energy of the ejection force storage member the ejection element is movable along an ejection element returning distance into closing direction after covering an ejection element ejecting distance.
 15. The drive device according to claim 4, wherein the ejection force storage member comprises a first spring base and a second spring base, wherein during tensioning of the ejection force storage member both spring bases are movable relative to a housing of the drive device and wherein during ejecting the first spring base is fixed relative to the housing and the second spring base is movable relative to the housing.
 16. The drive device according to claim 15, wherein the tensioning device comprises a first and a second movable tensioning element, each preferably being rotationally supported on the housing, wherein the first spring base of the ejection force storage member is mounted to the first tensioning element and the second spring base of the ejection force storage member is mounted to the second tensioning element.
 17. The drive device according to claim 16, wherein the second tensioning element forms the ejection element.
 18. The drive device according to claim 16, wherein during the over-pressing movement the first tensioning element and the second tensioning element are movable relative to each other and relative to the housing, whereby the ejection force storage member arrives from said relaxed or partly tensioned position in said tensioned position.
 19. The drive device according to claim 16, wherein during the ejection movement one of the tensioning elements, preferably the first tensioning element, is held to housing during at least a large part of the ejection movement by means of a holding device.
 20. The drive device according to claim 15, wherein in the closed position of the movable furniture part the ejection force storage member is in said relaxed or partly tensioned position, wherein the ejection force storage member is already partly tensioned when reaching the closed position by a closing movement of the movable furniture part.
 21. An item of furniture, comprising a furniture carcass, a movable furniture part and a drive device according to claim 1 for the movable furniture part. 